Cementitious material.



emupnsite used the)Y can hel practiealltT @inf/layed for plaxterinn iiiurpi'i'ses and have innen gre-atei' plastirity. unrhahilitjit and ultimate strength than Ordinar): hydrated liniel plante! plaster rainpesitiun was made by inenrpn-- ratingA with duhiinitir hydrated linie 159i nt thv mnpi ite irvnnth ineelerating material funuxuising natural reni-:nt ground together with uur-ci th :H mul-i. wvdiuni disullfate. n'liivh prndurw a wurpnsutmn ha ing gti-.id wurhahilitr and spreading pruiwrties and lhrsiralili:hardening' and early strengths w au to he murh '.zuperinr tu a curresmnding mixture nt' the natural rement and linie wilhuut the inem nnratiun of thi;- eaiperuul'tate nerg'ir/ing material. Thin fimnimaitinu when une partwm` tested with (uur parta nf (ltlawa Sand gare the tulhiwiug tensile strengths per uuuare inch: at "l luxure 'i pounds; .it days 2i Iinuniis: at T days 'ii pounds: at )h' days :l2 nmuuhl; al inuntlw (l2 pounds; the man nvsian hi'i rati-d linie. the rmuhined strength accelerating umterial rmuprising' natural eenunt and lwdiuni diaultute` and the sodium disultale vnergjixing! material uSOd in the foregoing vmnpnsitinn haring ahnut this inllnwinn analysts:

ulrrdnu @my li vnu l u i u nl Another suitahle plaster i'uinlimitiun wasl hrudlu'eil hy thuruughly iueuruu'ating with hydrated high i'ah'iulu liuu` 15% M the strength areeliaat-ing material rnuiprisiir;` natural rement and onewifghth as much of sodium disullate which had been ground tunelher with the natural rement so an in he thnroughly imorporated. This plaster cuninusitinu gare when Similarl'i' tested ihnvv i'ulluwiug tensile strengths: at 2l heurs.- lll punndu: at days 513 puunds; at 'T day..- {i pounds; at 28 da.\' pounds. this na'f al vement. lar-ing designated Nu. l iu the lfulhiwinn tal'le. Another `witahle plaster wuupnsitiun whiih had suinrwhat lesb satisfactory hardening pmperties when usnd as a wall plaster was made hy similarl)v incurpi'u'atingi with the. naine high rah'iuui hy drated linie 1512i, ui" Similar riuupiisite. strength :u'i'eleratiiuf material harmed luy `Inindingr together l tart nl' sodium disull l Natural l C 'ment L cement- #2.

23.68% in. 96% a4 957/' n illustrative plaster Composition formed hy intin'ialel): incorijin'ating S5 parts of hydrated high calcium linie and 15 parts-0f strength aecelerating material containing 1 part sediuni disul'fate. and 8 parts of tuned strength areleraling material containing alumina and silica and having ap? proxiuialrly the eumpositinn shown hy the i'ullnwing' ana' A gave when similarly tested they fnlluuinz tensile Strengths at Zllionrs 12 pounds. at. 2 da)y w pounds, at 'i' days 55 pnuiuls.: at Q :law a? puunds and at 3 months (3S pnund.

Silica, {Frith} 31.80 herrn" nid and alumina (Rigs) 15.68 VLinie ((atll 47.13 Magne-sia llilfjlll, 2.22 lmssonignitiun .84:

Another illustrative plaSter composition of' somewhat less strength was made by ineurporatinjl with hydrated dolomitic lime 15 per cent. of combined strength aeceleratingr material having Suhstantially the coninuutinn shown in the followingv analysis and farmed lu' `rrimliaif together one part of sndiuiu ilifuill'ate with eight parts of roasten" i'hiy. This pladir material when tested in the usual way showid 2S poundS tensile strength per square iuih at T days and l1 pounds at *2S days. l

Silica (5h01.) 66.92 Ferrie miid and alumina (R203) -1796 Lime (C210) .79 anni-aia (Mnt'l) Trace. Sulturic anhydrid (SOS) 6.82 Loss on ignition 7.28v

lt iS ot (nurse, nnderntood that the strength test. given in connection with the l" ie ;'uiu l rxauiphs munt he Considered in whim-limi with the. extreme difficultyot sevuriu;A reliahle. strength tests with linie plaster i-nniimsiiinns. These, tensile tests wem made nu hrliguels vhirnied in they regular Way l'ur veulent. renting'. the briquets being; kept in air. hut in autr. nt' all pogsible precautions wusiderahhvariatinns are likely to be found iu uurh resultsandit well understood that niuvh mure reliant-e, hunt. he placed 0n the praetieal wnrliing' results nf such plaster a ronSidei-ahle proportion of avaiiahle lime mixed with strength awfeleraling material therefor romprningg alnniina and iliea and eoperaling energiving: mauri-inl foinprising available anll'ilrir anhydrid loowly held in combination.

lJ. The snlistanliall)Y dry linel).v divided plaalie eninpositii .i emula-ning a large 'proportion ol' hydrated linie mixed with alnminous strength aeeelerating material and between about lire lo lilfleen per reni. :ila mneh eoiperating energizing' alkali metal snpernnll'ate energizing material.

2U. The snlihtantially dryv finely divided plastic compositions eompriaing a large proportion of hydrated lime mixed willi fused ealvinm ahiminate strength neeelerating inaterial eomhined with about one-eighth as mneli i odiinn disnlfate energizing material. 21. The substantially dry' finely divided plastic eomposition comprising a large proportion of available lime mixed with aluminona strength accelerating material with which hasl heen inem-porated sodium disull'ate energizing material.I

EDWARD L. CONWELL.

BENJAMIN ll. L'unLmv,

Numan Vll. Cnraxilin, Ji: 

